JP2006519281A - Method for making silicone emulsion - Google Patents

Abstract

Silanol-functional polysiloxane (I) is emulsified in water and the aqueous phase of the resulting emulsion is added to the formula XA-Si (R) _n (OR ') _3-n (II) (where X is an organic functional group). A represents a divalent organic bond, R represents a hydrocarbyl or substituted hydrocarbyl group, R ′ represents hydrogen or an alkyl or acyl group, respectively, and n = 0, 1, or 2. An organofunctional polysiloxane emulsion is prepared by adding an organofunctional silane and reacting the -OR 'group of (II) with the silanol group of polysiloxane (I) to form the organofunctional polysiloxane.

Description

  The present invention is useful in, for example, toiletries and cosmetics such as shampoos, conditioners and skin creams, textile treatments such as hydrophilic / hydrophobic modifiers and softeners, and car care and household cleaning products. It relates to the production of silicone oil emulsions. In particular, the present invention relates to the preparation of emulsions of organofunctional polysiloxanes, ie polysiloxanes containing organic functional groups such as amine groups, amide groups, epoxide groups, alcohol groups, thiol groups.

  U.S. Pat. No. 6,392,211 describes the production of emulsions of aminofunctional polysiloxanes by emulsifying low molecular weight or cyclic silicones and then reacting them with aminosilanes at elevated temperatures. US 6090885 describes the incorporation of amine functionality into a linear polyorganosiloxane in the presence of a cationic surfactant. U.S. Pat.No. 4,600,436 describes an amino functional silicone emulsion prepared by conducting emulsion polymerization from water, an emulsifier, a diorganopolysiloxane fluid, an amino functional silane, and optionally a polymerization catalyst. It is taught that cyclic or other low molecular weight siloxanes from which they are prepared can be stripped from emulsions of emulsion polymerized polysiloxanes.

In US Pat. No. 6090885, a terminal hydroxyl group polydimethylsiloxane is emulsified in water together with a cyclic polyorganosiloxane and polymerized to form a terminal hydroxyl group polydimethylsiloxane emulsion, which is then reacted with an amino functional silane. Is described. US Pat. No. 6,552,122 also describes a method of reacting a polydimethylsiloxane emulsion preformed by emulsion polymerization of a cyclic polyorganosiloxane with an aminofunctional silane.
U.S. Patent No. 6239211A U.S. Patent No. 6090885A U.S. Pat.No. 4,600,436A U.S. Pat.No. 6552122A

  Emulsions used in the personal care industry preferably have a reduced content of octamethylcyclotetrasiloxane (D4), a cyclic siloxane classified as harmful to reproduction. It is an object of the present invention to strip organic functional polysiloxanes, particularly amino functional polysiloxane emulsions having a lower D4 content than aminofunctional polysiloxane emulsions prepared by emulsion polymerization as described above. There is to be prepared without.

The process for preparing an emulsion of organofunctional polysiloxane according to the present invention mechanically emulsifies silanol functional polysiloxane (I) in water in the absence of basic and acidic silanol polycondensation catalysts. And the aqueous phase of the resulting emulsion has the formula XA-Si (R) _n (OR ') _3-n (II) (wherein X represents an organic functional group and A represents a divalent organic bond) R represents a hydrocarbyl or substituted hydrocarbyl group, R ′ represents hydrogen or an alkyl or acyl group, respectively, n = 0, 1, or 2), and Forming an organofunctional polysiloxane by reacting the —OR ′ group of (II) with the silanol group of polysiloxane (I).

  The silanol functional polysiloxane (I) is preferably a substantially linear polydiorganosiloxane fluid such as polydimethylsiloxane, although branched polysiloxanes may also be used. The silanol group is preferably a terminal group of a polysiloxane chain. The viscosity of the polysiloxane fluid may be, for example, at least 0.02 Pa.s to 1000 Pa.s (20 to 1000000 cps), preferably 0.5 to 40 Pa.s. Most preferably, the molecular weight of the silanol functional polysiloxane (I) is close to the desired final molecular weight of the desired organofunctional polysiloxane. Both emulsification of (I) and reaction with organofunctional silane (II) are preferably carried out under conditions that do not promote fast polycondensation of polysiloxane (I).

  This silanol-functional polysiloxane (I) is mechanically emulsified in water in the absence of acidic and basic silanol polycondensation catalysts. The silanol-functional polysiloxane (I) is preferably emulsified continuously, but alternatively, it may be emulsified batchwise. In a preferred procedure, silanol functional polysiloxane (I), at least one surfactant, and water are continuously fed to a high shear mixer in such a ratio that a viscous oil-in-water emulsion is formed. This is continuously recovered from the mixer, diluted and then the organofunctional silane (II) is added.

  The amount of surfactant is usually at least 0.2%, preferably at least 0.5%, for example from 2% to 10 or 20%, based on the weight of the silanol-functional polysiloxane (I). The amount of water present (including any moisture present in the surfactant composition) is usually at least 0.5%, preferably at least 1% up to 10 or 20%, based on the polysiloxane fluid, It can be 30%. The polysiloxane content of the mixture fed to the high shear mixer is preferably 70 to 99% by weight, most preferably 80 to 98%. Non-Newtonian “thick phase” emulsions formed by such ratios of polysiloxane, surfactant, and water are those that exhibit very high viscosity at low shear rates. This high polysiloxane content mixture is more easily emulsified with a smaller particle size than a dilute mixture.

  Mechanical emulsification through such a “concentrated phase” is most effectively carried out as a continuous process. A particularly preferred procedure is described in WO 02/42360. High shear mixers such as those sold under the trademark "TK Products Homomic Line Mill" or "Bematek" or "Greerco" or "Ross" Even in-line type dynamic rotor / stator devices (often referred to as colloid mills) and rotary disk mixers of the type described in JP-A-2000-449 can be used for plastic extrusion. It may be the type of twin screw mixer used.

  The surfactant used for emulsifying the silanol-functional polysiloxane (I) is preferably one or more nonionic surfactants. Examples of nonionic surfactants include polyoxyalkylene alkyl ethers such as polyethylene glycol long chain (9 to 22 C, particularly 12 to 14 C) alkyl ether, polyoxyalkylene sorbitan ethers, polyoxyalkylene alkoxylate esters, polyoxyalkylene esters, and the like. Examples include alkylene alkyl phenol ethers, ethylene oxide propylene oxide copolymers, polyvinyl alcohol, glyceride esters, and alkyl polysaccharides. In general, it is unlikely that a nonionic surfactant will catalyze polycondensation of polysiloxanes.

Alternatively, ionic surfactants such as cationic, amphoteric, and / or anionic surfactants may be used. Examples of the cationic surfactant include quaternary ammonium salts such as 8-22C alkyltrimethylammonium halide, 8-22C alkyldimethylbenzylammonium halide, and di (8-22C alkyl) dimethylammonium halide. Suitable amphoteric surfactants include, for example, coconut oil fatty acid amide propyl betaine, coconut oil fatty acid amide propyl hydroxysulfate, coconut oil alkyl betaine, coconut oil fatty acid amide sodium acetate, coconut oil alkyl dimethyl betaine, N-coconut oil alkyl- Examples include 3-aminobutyric acid and imidazolinium carboxyl compounds. Examples of the anionic surfactant include alkyl sulfates such as lauryl sulfate, polymers such as acrylic ester / acrylic acid C _10-30 alkyl ester crosspolymer, (6-20C alkyl) benzenesulfonic acid and salts, mono Examples include sulfates of alkyl polyoxyethylene ethers, sulfonated fatty acid glyceryl esters, and salts of sulfonated monohydric alcohol esters. Some anionic surfactants such as sulfonic acids have catalytic activity for condensation polymerization of silanol-functional polydiorganosiloxanes. This catalytic activity can be suppressed by a neutralizing agent such as an organic amine such as triethanolamine or an inorganic base such as sodium hydroxide. In steps involving controlled polymerization of (I), it is generally preferred to avoid the use of anionic surfactants except where required for emulsification of silanol functional polysiloxane (I).

  When the silanol-functional polysiloxane (I) is emulsified as a “concentrated phase”, it is preferable to dilute it before adding the organofunctional silane (II). Preferably, the concentration of polysiloxane (I) in the emulsion at the time of reaction with the organofunctional silane (II) is 20 to 75% by weight. This “concentrated phase” dilution may be carried out with water alone or with a mixture of water and a surfactant. The surfactant used at the time of dilution may be any of the types described above. This surfactant will be selected for best miscibility with the organofunctional silane (II). For example, when the organic functional group (II) is an amino group, a cationic surfactant may be used for the dilution step. Alternatively, nonionic surfactants are generally suitable for dilution purposes.

The organofunctional silane of formula XA-Si (R) _n (OR ′) _3n (II) is most preferably an aminosilane. The present invention is particularly suitable for the production of aminofunctional polysiloxane emulsions useful for toiletries and cosmetics such as shampoos and skin creams. Therefore organic functional group X is preferably a primary, secondary, or tertiary amine groups, for example whether it is -NH ₂ or -NHC ₂ H ₅ or the like -NHC ₂ H ₄ NH ₂ It may be a group containing both primary and secondary amino.

  Alternatively, the organic functional group X may be an amide, epoxide, alcohol, or thiol group.

  The OR ′ group in (II) is preferably an alkoxy group, and R ′ is preferably an alkyl group, more preferably 1 to 4C alkyl. The R group (if present) is also preferably 1-4C alkyl. Most preferably, each R ′ group of silane (II) is a methyl group. The inventors have found that methoxysilane is more reactive than ethoxysilane or higher alkoxysilanes, so that aminosilanes containing methoxy groups are more easily incorporated into polysiloxanes. Particularly preferred organofunctional silanes (II) include, for example, 3-aminopropyltrimethoxysilane and 3- (2-aminoethylamino) propyltrimethoxysilane.

  The molar ratio of silanol groups of (I) to alkoxy or other groups OR ′ bonded to Si of organosilane (II) is preferably in the range of (0.4 to 1.5: 1). In many cases, it is preferred that the molar ratio of silanol groups of (I) to alkoxy groups bonded to Si of aminosilane (II) is less than 1: 1, so that amino- or other organofunctional alkoxy The blocking of silanol-functional polysiloxane (I) by silane (II) occurs as the main reaction. If it is desirable to also undergo chain extension polymerization of (I) to produce an organofunctional polysiloxane with a higher degree of polymerization than the starting silanol functional polysiloxane (I), the silanol group pair of (I) It would be preferred that the molar ratio of alkoxy groups bonded to Si of aminosilane (II) be greater than 1: 1.

  When the organofunctional silane (II) is an amino or amide functional silane, the reaction with the polysiloxane (I) is a cationic surfactant that is added to the emulsion before adding the organofunctional silane (II) It is preferable to carry out in the presence of. When emulsifying polysiloxane (I) as a “concentrated phase” and diluting it before reacting with organofunctional silane (II), there is a cationic surfactant in the water in the dilution step as described above. You may let them. Alternatively, the cationic surfactant may be added with the aminosilane (II) or after the emulsion is diluted and before (II) is added. The addition amount of the cationic surfactant may be, for example, 1 to 10% based on the total weight of the siloxane reagent.

  Preferably, a base is added to the emulsion to catalyze the reaction of (II) —OR ′ groups with the silanol groups of polysiloxane (I). This base may be added to the emulsion prior to, simultaneously with, or after the organofunctional silane (II). This base is preferably an inorganic base such as sodium hydroxide or potassium hydroxide, or an amine such as triethanolamine. The amount of base is preferably that amount necessary to achieve pH 9-13, most preferably 11-12.

  The reaction between the organofunctional silane (II) and the silanol functional polysiloxane (I) is preferably carried out at a temperature below 40 ° C., most preferably below 30 ° C., for example at 10-25 ° C., which is room temperature. The present inventors have found that it is particularly effective to produce an emulsion having a small amount of D4 by performing the reaction between (I) and (II) at a low temperature. The reaction time may be, for example, 0.5 to 24 hours.

  Organofunctional polysiloxane emulsions prepared by the process of the present invention typically contain less than 2% by weight of cyclic polysiloxanes, especially less than 2% D4, based on the total weight of polysiloxanes in the emulsion. By maintaining the temperature below 30 ° C. in the reaction of (I) and (II), an emulsion of aminosiloxane having a D4 content of less than 1% can be produced.

  The emulsion of the present invention is particularly advantageous for personal care applications such as toiletries and cosmetics such as shampoos and skin creams, where emulsions having a low D4 content are particularly required. It is also advantageous for car care.

  The following examples illustrate the invention. All parts and percentages are by weight.

  By substantially processing 60 parts of a substantially linear hydroxy end-capped polydimethylsiloxane having a viscosity of 4000 mPa.s. using a high shear mixer as illustrated in FIG. 1 of WO 02/42360, Emulsified with 2.5 parts Renex 30 ™ nonionic surfactant and 1.33 parts water. The resulting thick phase emulsion was batch diluted with water until 50% silicone in a stirred reactor, followed by Arquad 16-29TM 30% active cationic surfactant 5.87. Parts were added. 0.5 part of 50% aqueous sodium hydroxide and 7 parts of 3- (2-aminoethylamino) propyltrimethoxysilane were added. This emulsion was reacted at room temperature (23 ° C.) for 6 hours. An aminosiloxane emulsion having a particle size of 200 nm was obtained. D4 contained in the final emulsion constituted 0.7% of the silicone phase.

  When the hair application test was performed, the same performance as that of a commercially available aminosiloxane emulsion having a D4 content of 6.6% was shown.

35 parts of a substantially linear hydroxy end-capped polydimethylsiloxane having a viscosity of 4000 mPa.s was batch processed (KlaussenTM 10 liter change with scraper blades and two high speed discs for dispersion Emulsified with 2.9 parts Linex 30 ™ nonionic surfactant, 1.7 parts Servamine KAC458 ™ cationic surfactant, and 1.33 parts water. The mixture was diluted with 55.8 parts water. 1.8 parts of ARCARD 16-29 ™ 30% active cationic surfactant, 0.5 part of 3- (2-aminoethylamino) propyltrimethoxysilane, and 0.5 part of 40% NaOH solution were added with stirring. The emulsion was reacted at room temperature (23 ° C.) for 8 hours, and then neutralized with 0.5 part of glacial acetic acid. An aminosiloxane emulsion having an average particle size of 170 nm was obtained. The amine content by aminopotentiometric titration was 0.124 meq / g, the final pH was 7.6, the viscosity of the extracted polymer phase was 6500 cp, and the D4 content of the silicone phase was 0.76% by weight.

Claims (10)

Silanol-functional polysiloxane (I) is mechanically emulsified in water in the absence of basic and acidic silanol polycondensation catalysts,
In the aqueous phase of the resulting emulsion, the formula XA-Si (R) _n (OR ') _3-n (II) (wherein X represents an organic functional group, A represents a divalent organic bond, R Each represents a hydrocarbyl or substituted hydrocarbyl group, R ′ represents hydrogen or an alkyl or acyl group, respectively, n = 0, 1, or 2), and
A method for preparing an emulsion of an organofunctional polysiloxane, comprising forming an organofunctional polysiloxane by reacting the —OR ′ group of (II) with the silanol group of the polysiloxane (I).   The method according to claim 1, wherein the silanol-functional polysiloxane (I) is emulsified in the presence of a nonionic surfactant.   The silanol-functional polysiloxane (I), at least one surfactant, and water are continuously fed to a high shear mixer in a ratio to form a viscous oil-in-water emulsion, the emulsion being 3. The method according to claim 1 or 2, wherein the organofunctional silane (II) is added after continuously collecting and diluting from a mixer.   4. The method according to claim 1, wherein the organic functional group X of silane (II) is an amino group.   5. The method according to claim 1, wherein each of the R ′ groups of silane (II) is a methyl group.   6. The method of claim 5, wherein the organofunctional silane is 3-aminopropyltrimethoxysilane.   The method according to any one of claims 1 to 6, wherein a cationic surfactant is added to the emulsion before adding the organofunctional silane (II).   The method according to any one of claims 1 to 7, wherein a base is added to the emulsion in order to catalyze the reaction between the -OR 'group of (II) and the silanol group of the polysiloxane (I).   The method according to any one of claims 1 to 8, wherein the organofunctional silane (II) and the silanol functional polysiloxane (I) are reacted at a temperature of less than 40 ° C. 10. An emulsion of organofunctional polysiloxane prepared by the method of any one of claims 1 to 9 comprising less than 2% by weight of cyclic polysiloxane based on the total weight of polysiloxane in the emulsion.